Element loss with layers that have identical names

[nathanacurtis]

Problem

When multiple layers in the same variant share the same name (e.g., two sibling frames both named "Content"), one silently overwrites the other during generation. This causes missing elements in the output spec with no error or warning.

Solution

Either deduplicate layer names automatically using a deterministic algorithm (e.g., combining the name with the element type), or emit a warning identifying the duplicate names and which variant they occur in. No elements should be silently lost.

Acceptance criteria

• Duplicate sibling layer names are detected during generation
• Names are deduplicated deterministically, or a diagnostic is emitted
• No silent data loss in the output spec

---

Implementation details are tracked internally.